PCI: aardvark: Fix initialization with old Marvell's Arm Trusted Firmware

Old ATF automatically power on pcie phy and does not provide SMC call for
phy power on functionality which leads to aardvark initialization failure:

[    0.330134] mvebu-a3700-comphy d0018300.phy: unsupported SMC call, try updating your firmware
[    0.338846] phy phy-d0018300.phy.1: phy poweron failed --> -95
[    0.344753] advk-pcie d0070000.pcie: Failed to initialize PHY (-95)
[    0.351160] advk-pcie: probe of d0070000.pcie failed with error -95

This patch fixes above failure by ignoring 'not supported' error in
aardvark driver. In this case it is expected that phy is already power on.
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Link: https://lore.kernel.org/r/20200902144344.16684-3-pali@kernel.org
Fixes: 36669701 ("PCI: aardvark: Add PHY support")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: <stable@vger.kernel.org> # 5.8+: ea17a0f1: phy: marvell: comphy: Convert internal SMCC firmware return codes to errno

drivers/pci/controller/pci-aardvark.c

@@ -1081,7 +1081,9 @@ static int advk_pcie_enable_phy(struct advk_pcie *pcie)
 	}
 
 	ret = phy_power_on(pcie->phy);
-	if (ret) {
+	if (ret == -EOPNOTSUPP) {
+		dev_warn(&pcie->pdev->dev, "PHY unsupported by firmware\n");
+	} else if (ret) {
 		phy_exit(pcie->phy);
 		return ret;
 	}